I took off a three-mile hike this evening. Before leaving I had the following functions operational on my Garmin 76C gps. All these function draw power.
1. Unit on, by default always searching for additional satellites.
2. Navigation to waypoint on.
3. Bearing pointer operational with compass dial operating in background.
4. Trip computer page functional.
5. Stop Watch functioning.
6. Track Mode on.
7. Position Arrow functional on the map page.
I would call the power bar at a weak 2. II
On the return trip I notice the power bar had dropped down to one. I out of IIII. At this point the Bearing Point and Compass were no longer providing correct data. Based on this experience today and on other occasions when the power level gets close to shutting the unit off some functions are automatically shut down early so the unit will still function. In this case the pointer. If I had followed the pointer I would have gone 180° away from my goal.
During the walk I would stop and check the different pages, which turned on the backlight. This was intentional to draw the battery down.
Lesson Learned: When in the field and the power level drops below two bars the first time, install fresh batteries. Especially if you are in a night navigation situation. You want to do the battery change under your terms, not when you are in a critical situation. If you are using a mapping gps, or navigating towards a waypoint on your unit, goto the Map Page. The Position Arrow has always worked for me until the batteries have gone dead. A lot of times I will navigate to a waypoint on the map page by using the Position Arrow when I have good batteries.
Just before shutting down completely the unit will give you a low battery warning.
